This invention relates to a baffle seat for a pressure regulator for automotive fuel systems, and more particularly to a baffle seat having a geometry which reduces the noise associated with high fuel flow rates through the baffle seat.
Most modern automotive fuel systems utilize fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which fuel is supplied by a pump. The pressure at which the fuel is supplied to the fuel rail must be metered to ensure the proper operation of the fuel injectors. Metering is carried out using pressure regulators which control the pressure of the fuel in the system at all engine r.p.m. levels.
Known pressure regulators, as shown in FIG. 5, employ a spring biased valve seat with a longitudinal flow passage. A detailed view of a known valve seat is shown in FIG. 6. The valve seat is biased to a closed position to prevent the flow of fuel through the pressure regulator at low fuel pressures. As fuel pressure builds in the system, the pressure against the valve seat overcomes the biasing force of the spring, allowing fuel to flow through the valve seat, thereby controlling the fuel pressure in the system.
Fuel flow rate, measured in liters per hour, through known pressure regulators tends to be low at high engine speed; measured in revolutions per minute, as large quantities of fuel are consumed in the combustion process. And at low engine speeds, less fuel is consumed in combustion and flow rates through the pressure regulators are high. These high fuel flow rates through known pressure regulator valve seats produce unacceptably high noise levels. A valve seat is needed that maintains flow noise within acceptable levels, even at high fuel flow rates.
The present invention provides a flow-through pressure regulator which maintains a substantially constant noise output from low fuel flow rates to high fuel flow rates. The flow-through pressure regulator includes a housing having an inlet and an outlet offset along a longitudinal axis. The housing is separated by a divider into a first chamber and a second chamber. The divider has a passage that communicates the first chamber with the second chamber. The passage includes a first section extending along the longitudinal axis and a second section extending transverse to the longitudinal axis. A closure member permits or inhibits flow through the passage.
The divider can include a baffle seat that is suspended by the divider in the housing and provides the passage. The baffle seat has a first seat portion and a second seat portion disposed along the longitudinal axis on opposite sides of the divider such that the first seat portion is disposed the first chamber and the second seat portion is disposed in the second chamber. The first section of the passage extends along the longitudinal axis through the first portion and into the second portion of the seat. The second section of the passage extends transverse to the longitudinal axis in the second portion of the seat.
The baffle seat can comprise a first surface disposed in the first chamber, a second surface disposed in the second chamber, and a side surface disposed between the first surface and the second surface. The first section of the passage communicates with the first surface and the second section communicates with the side surface. The first section has a first wall extending from the first surface of the seat to an end wall within the second portion of the seat, and the second section has a second wall extending from the first wall to the side surface. The second wall extends from the first wall to diametrically opposed locations on the side surface, and intersects the first wall proximate the end wall.
In a preferred embodiment, the divider is a diaphragm, and a first biasing element is located in the second chamber. The closure member includes a ball disposed in a retainer. The housing includes a first cup-shaped member and a second cup-shaped member. In a preferred embodiment, the flow-through pressure regulator of the present invention has a sound rating in Sones that remains substantially constant from a low fuel flow rate to a high fuel flow rate.
The present invention also provides a low noise baffle seat for a flow-through regulator. The baffle seat has an exit geometry which reduces output noise levels at high fuel flow rates. The baffle seat includes a first seat portion having a first surface disposed about a central axis, a second seat portion having a second surface offset from the first surface along the central axis, a side surface disposed between the first surface and the second surface and a passage extending from the first surface through the first portion and the second portion to the side surface. The passage has a first section and a second section. The first section of the passage extends along the central axis in both the first portion and the second portion of the baffle seat. The second section of the passage extends transverse to the longitudinal axis in the second portion of the baffle seat. The first section communicates with the first surface and the second section communicates with the side surface.
The present invention also provides a method of stabilizing noise generation in a flow-through regulator. The flow-through regulator includes a housing with an inlet and an outlet offset along a longitudinal axis, a divider separating the housing into a first chamber and a second chamber, a passage through the divider that provides communication between the first chamber and the second chamber, and a closure member that permits or inhibits flow through the passage. The method is achieved by providing the passage with a first section extending along the longitudinal axis and a second section extending transverse to the longitudinal axis, and communicating the first section with the first chamber and the second section with the second chamber.